wasmtime_wasi_http/
lib.rs

1//! Wasmtime's implementation of `wasi:http`
2//!
3//! This crate is organized similarly to [`wasmtime_wasi`] where there is a
4//! top-level [`p2`] and [`p3`] module corresponding to the implementation for
5//! WASIp2 and WASIp3.
6
7#![deny(missing_docs)]
8#![doc(test(attr(deny(warnings))))]
9#![doc(test(attr(allow(dead_code, unused_variables, unused_mut))))]
10#![cfg_attr(docsrs, feature(doc_cfg))]
11
12use http::{HeaderName, header};
13
14mod ctx;
15#[cfg(feature = "default-send-request")]
16mod default_send_request;
17mod error;
18mod field_map;
19#[cfg(feature = "component-model-async")]
20pub mod handler;
21pub mod io;
22#[cfg(feature = "p2")]
23pub mod p2;
24#[cfg(feature = "p3")]
25pub mod p3;
26mod request_options;
27
28pub use ctx::*;
29#[cfg(feature = "default-send-request")]
30pub use default_send_request::*;
31pub use error::*;
32pub use field_map::*;
33pub use request_options::*;
34
35/// Extract the `Content-Length` header value from a [`http::HeaderMap`], returning `None` if it's not
36/// present. This function will return `Err` if it's not possible to parse the `Content-Length`
37/// header.
38#[cfg(any(feature = "p2", feature = "p3"))]
39fn get_content_length(headers: &http::HeaderMap) -> wasmtime::Result<Option<u64>> {
40    let Some(v) = headers.get(header::CONTENT_LENGTH) else {
41        return Ok(None);
42    };
43    let v = v.to_str()?;
44    // RFC 9110 defines `Content-Length` as `1*DIGIT`. `u64`'s `FromStr` is more
45    // lenient and also accepts a leading `+`, so reject anything that isn't a
46    // non-empty run of decimal digits before parsing.
47    if v.is_empty() || !v.bytes().all(|b| b.is_ascii_digit()) {
48        wasmtime::bail!("invalid `content-length` header value: {v:?}");
49    }
50    let v = v.parse()?;
51    Ok(Some(v))
52}
53
54#[cfg(all(test, any(feature = "p2", feature = "p3")))]
55mod content_length_tests {
56    use super::get_content_length;
57    use http::{HeaderMap, HeaderValue, header};
58
59    fn headers(value: &str) -> HeaderMap {
60        let mut map = HeaderMap::new();
61        map.insert(
62            header::CONTENT_LENGTH,
63            HeaderValue::from_str(value).unwrap(),
64        );
65        map
66    }
67
68    #[test]
69    fn content_length_must_be_decimal_digits() {
70        assert_eq!(get_content_length(&HeaderMap::new()).unwrap(), None);
71        assert_eq!(get_content_length(&headers("0")).unwrap(), Some(0));
72        assert_eq!(get_content_length(&headers("1234")).unwrap(), Some(1234));
73
74        // `u64::from_str` accepts these but they are not `1*DIGIT` per RFC 9110.
75        assert!(get_content_length(&headers("+5")).is_err());
76        assert!(get_content_length(&headers("-5")).is_err());
77        assert!(get_content_length(&headers(" 5")).is_err());
78        assert!(get_content_length(&headers("")).is_err());
79    }
80}
81
82/// Set of [http::header::HeaderName], that are forbidden by default
83/// for requests and responses originating in the guest.
84pub const DEFAULT_FORBIDDEN_HEADERS: [HeaderName; 9] = [
85    header::CONNECTION,
86    HeaderName::from_static("keep-alive"),
87    header::PROXY_AUTHENTICATE,
88    header::PROXY_AUTHORIZATION,
89    HeaderName::from_static("proxy-connection"),
90    header::TRANSFER_ENCODING,
91    header::UPGRADE,
92    header::HOST,
93    HeaderName::from_static("http2-settings"),
94];
wasmtime_wasi_http/lib.rs

wasmtime_wasi_http/
lib.rs
